Largest European airline company Lufthansa Group said on Wednesday that its Supervisory Board approved the purchase of 20 planes of the 787-9 model from the Boeing Co. and 20 of A350-900 models from Airbus SE, to be delivered from 2022 to 2027.

The company said in the statement that it agreed with sellers not to reveal the actual price of the orders, which have "a list-price investment volume of $12 billion." It is yet to be announced which airlines will deploy the aircraft and at which hubs.

"By replacing four-engine planes with new models, we are laying a sustainable foundation for our future in the long run. In addition to the cost-effectiveness of the A350 and B787, the significantly lower C02 emissions of this new generation of long-haul aircraft was also a decisive factor in our investment decision. Our responsibility for the environment is becoming more and more important as a criterion for our decisions," said CEO and Chairman of Lufthansa, Carsten Spohr.

The German airline will also sell six of its 14 Airbus A380 planes back to the manufacturer and return them in 2022 and 2023, the statement added.